The present invention relates to railway vehicle trucks and more particularly to the side frame in a truck having a single wheelset.
Traditionally, a truck for use with a railway vehicle has at least a pair of spaced wheelsets and is commonly called a 4-wheel truck. Each wheelset comprises two wheels joined to a free axle wherein the wheels and respective axle rotate as a unit. Such trucks were developed to support considerable loads and today are available with railway cars having rated capacities of 100 tons or greater.
When the railway vehicle is not required to carry such heavy loads, for example in passenger service or piggy-back type service of automotive trailers or containers, then the load carrying capacity of the truck may be reduced substantially.
One suggested railway vehicle truck particularly adapted for lighter loads includes a single wheelset. The wheelset has its axle ends rotatively journaled in bearings. The bearings in turn operatively connect through an adapter to a centrally located pedestal jaw integrally formed as part of each of a pair of spaced longitudinally positioned side frames.
At each side frame end is an inwardly projecting bracket which in turn pivotally supports an upper end of a swing hanger. Positioned laterally between the front and rear swing hanger pairs is a swing hanger stabilizer beam assembly. Each assembly has a pair of end caps which pivotally connect respectively with a lower end of each swing hanger pair.
Because the upper side frame bracket-swing hanger pivot connections are located apart at a lesser distance than the lower swing hanger stabilizer beam assembly end cap-swing hanger pivot connections, the swing hanger stabilizer beam assembly is self leveling. Each swing hanger stabilizer beam assembly end cap has a pair of caps which contain the lower ends of a set of springs. Upper ends of the spring sets are operatively connected to a body of the railway vehicle and resiliently support such.
The railway truck as described above in theory provides certain advantages over the traditional 4-wheel truck. First, the mass of the truck is reduced. This lesser mass between the track and the car body reduces track wear and reduces the energy required to move the railway vehicle body associated with the truck. This mass can be further minimized by using components having an optimum strength-to-weight ratio.